will addding a box to the exhaust reduce performance?

Hi,

I have a longlife exhaust on my car mk2 abf, when i got it fitted i told the fitter i wanted it quiet, but its never been that and is quite noisy between 2500 rpm and 4000 rpm. from looking underneath there is no silencer between the front and rear box.

my question is, if i get one fitted will i lose performance? the car made 157 bhp and 144 lbft of torque on the rollers the other day and i wouldnt want to reduce that.

also while there shall i get the lambda sensor fitted as im running without it at the moment?

 

The lambda sensor will improve fuel economy during closed loop operation and limit the rich clip at wide open throttle.

 

the lambda sensor normally goes in the downpipe, doesn't it?

Another box won't make much difference, as long as it's a straight through. It's worth checking that the exhaust isn't vibrating on the rear beam axle, as your car is very low. In that case, another box won't help you.

 

yup, the lambda will have to go in the downpipe, i'll get that fitted then, i cant be having poor fuel economy.

The pipe work is clearing the beam with no issues, its just too loud for my liking when driving, there is space for the extra box so as long as its straight through i should be ok?

Thanks,
G

 

So how many boxes has it got, in total? The little one on the downpipe, and one at the back?

 

just a quick one i put a 20l 16v 9a on carbs in car not so long on standard exhaust i thougth it was a little to quite so cut the first box out and tbh it doesnt sound any different

so all im sayin is if u put that one back in it might not make any differnce to yours

 

i got a small box just after the downpipe and backbox itself. a few people have mentioned that the box that im missing makes the most difference to loudness.

 

The box you need is the one that sits behind the back box right behind the rear axle. Its the big square one. The system can be straight through all the way from the engine to this box and it won't get any louder.

Gurds

 

If your not happy with the system go back to the fitter and explain the issues. I'm sure they'll sort it.

 

I've got a manifold back Longlife system on my valver including centre, middle and rear boxes and it's only loud when you want it to be! As above I think it's the transverse silencer by the axle that has the most effect.

 

Thanks for the input. im going to go for a vw centre box to reduce noise levels, i'll post up the verdict once fitted.

G

 

I had been back already and the service i got was rude, so id rather not go back.

 

All the more reason to perdue it, and with their head office if necessary! ESPECIALLY as longlife advertise with a big banner advert on this very site

 

It was a while ago, but point taken, will give them a call later.

 

yet to speak to longlife.

But, called vw to get the price on the centre box and have been told they are obsolete now.

Euro have what they are claiming to be the original one in stock for resonable money, does anyone have experience of euro car parts exhausts?

 

Guys am i better off with a euro car parts replacement middle box or a used standard box of unknown use as the part is now obsolete and no dealers have stock?

 

not sure what ECP stock, but GSF stock ernst which are OK, but be aware that ernst silencers are only zinc plated and that can react with stainless. i'd go back to longlife and get a stainless straight-thru centrebox fitted personally.